joint actuator sequencing

I have a simple question:

Suppose I have three different joints being actuated through three different joint actuators. I also have a function that generates the positions or angles through which those joints must move in a definite sequence, say j2 then j1 then j3. How can something like this be implemented in Simulink?

[Syed]

Just to clarify: I already have the Simulink model - all I need to know is how to ensure that the joints are actuated in the required sequence.